feat(repo): Add GitHub About sync command

Expose an explicit sync:github-about workflow that updates the remote GitHub About description, homepage, and topics from the repository metadata source of truth.

Add regression coverage for the generated gh commands and document the new maintainer path in the changelog and walkthrough.

tools/scripts/tests/test_sync_repo_metadata.py

@@ -120,6 +120,37 @@ If you want a faster answer than "browse all 1,273+ skills", start with a tool-s
         self.assertIn("1,304+ agentic skills", description)
         self.assertIn("installer CLI", description)
 
+    def test_sync_github_about_builds_expected_commands(self):
+        calls = []
+
+        def fake_runner(args, dry_run=False):
+            calls.append((args, dry_run))
+
+        sync_repo_metadata.sync_github_about(
+            {
+                "repo": "sickn33/antigravity-awesome-skills",
+                "total_skills_label": "1,304+",
+            },
+            dry_run=True,
+            runner=fake_runner,
+        )
+
+        self.assertEqual(len(calls), 2)
+        repo_edit_args, repo_edit_dry_run = calls[0]
+        topics_args, topics_dry_run = calls[1]
+
+        self.assertTrue(repo_edit_dry_run)
+        self.assertTrue(topics_dry_run)
+        self.assertEqual(repo_edit_args[:4], ["gh", "repo", "edit", "sickn33/antigravity-awesome-skills"])
+        self.assertIn("--description", repo_edit_args)
+        self.assertIn("--homepage", repo_edit_args)
+        self.assertIn("https://sickn33.github.io/antigravity-awesome-skills/", repo_edit_args)
+
+        self.assertEqual(topics_args[:4], ["gh", "api", "repos/sickn33/antigravity-awesome-skills/topics", "--method"])
+        self.assertIn("PUT", topics_args)
+        self.assertIn("names[]=claude-code", topics_args)
+        self.assertIn("names[]=skill-library", topics_args)
+
 
 if __name__ == "__main__":
     unittest.main()